Blue anthrarufin dye and process of making same.



ROBERT E. SCHMIDT, OF ELBERFELD, GERMANY, ASSIGNOR TO THE FAR-BENFABRIKEN OF ELBERFELD COMPANY, OF NEW YORK, N. Y.

BLUE ANTHRARUFIN DYE AND PROCESS OF MAKING SAME.

SPECIFICATION forming part of Letters Patent No. 656,668, dated August28, 1900.

Application filed August 15, 1899.

To all whom it may concern:

Be it known that I, ROBERT E. SCHMIDT, doctor of philosophy, chemist,(assignor to the FARBENFABRIKEN OF ELBERFELD COMPANY, of New York,)residing at Elberfeld,Germany, have invented a new and usefulImprovement in Dyes Derived from Anthrarufin; and I hereby declare thefollowing to be a clear and exact description of my invention.

In the specification to Letters Patent No. 595,349 I have described themanufacture of a disulfonic acid of paradiamidoanthrarufin having theformula NH, 1 OH (8) on (4 2 I have found that avaluable new benzylateddyestuff can be obtained by subjecting the said disulfonic acid to theaction of benzyl chlorid.

In carrying out my new process practically I can proceed as follows,(the parts being by Weight:) Eight parts of benzyl chlorid are slowlyintroduced, with energetic stirring, into a solution prepared from tenparts of diamidoanthrarufindisulfonic acid and five hundred parts of hotwater, the temperature of the solution being kept at about from 80 to 90centigrade. Stirring is continued at the same temperature until a testportion when dissolved in concentrated sulfuric acid and mixed withboric acid is found to exhibit no longer the characteristic absorptionspectrum of the boric-acid ether of the dianiidoanthrarufindisulfonicacid. When this stage is reached,the new benzylated dyestutf (whichbegins to separate partially from. the reaction mixture even when stillhot) is completely precipitated by cooling the reaction mixture and bythe addition of a concentrated common-salt solution. The coloring-matteris finally filtered off, dried, and pulverized. It is thus obtained inthe shape of a blue powder.

The dyestuff is soluble in water with a blue color, which is moregreenish blue than that of a watery solution of thediamidoanthrarufindisulfonic acid. On adding strong hydrochloric acid tothe watery solution of the new dyestuff the latter is precipitated, thecolor of the solution not being changed into violet.

The new benzylated dyestuff is easily soluble in alcohol. Byconcentrated sulfuric acid it is dissolved with a yellow color, whichchanges into green on the addition of boric acid.

The new dyestuff dyes unmordanted wool in acid-baths bright-blue shadesand yields on chromemordanted wool greenish blue shades.

Having now described my invention and in what manner the same is to beperformed, what I claim as new, and desire to secure by Letters Patent,is-- p 1. The process for producing a new benzylated derivative fromdiamidoanthrarufindisulfonic acid which process consists in firstheating a mixture prepared from a watery solution ofdiamidoanthrarufindisulfonic acid and benzyl chlorid, secondlyprecipitating the new dyestuff from the reaction mixture and finallyisolating the same, substantially as hereinbefore described.

2. As a new article of manufacture the new benzylated anthrarufindyestuft being when dry and pulverized a blue powder soluble in waterwith a blue color from which solution on the addition ofstronghydrochloric acid the dyestuff is precipitated the color of thesolution being, however, not changed intoviolet, easily soluble inalcohol, being dissolved by concentrated sulfuric acid with a yellowcolor which is changed into green on the addition of boric acid, dyeingunmordanted wool bright-blue shades, yielding on chrome mordauted woolgreenish-blue shades,- substantially as hereinbefore described.

In testimony whereof I have signed my name in the presence of twosubscribing witnesses.

ROBERT E. SCHMIDT.

